Version 51 Super Octopus RM Kit CW Transceiver Telegraph Shortwave Radio | Instrument Parts & Accessories

Version 51 Super Octopus RM Kit CW Transceiver Telegraph Shortwave Radio | Instrument Parts & Accessories

Unavailable in Russian Federation

Type1:The main board parts need to be welded by yourself (without shell)

Type2:Shell (excluding other components)

The welding of this kit requires a certain foundation of electronic technology. It can recognize components and welding. Basically, the entry machine does not need to be debugged. As long as it is assembled carefully according to the kit instructions, it will succeed.

Note: The MOS field effect tube 2N7000 in the kit should be soldered as the last component. In order to prevent electrostatic breakdown, the soldering iron power supply should be disconnected and soldered with waste heat.

a brief introdction       "Super octopus" (Super RM) was first launched by the US SWL laboratory in 2002, formerly known as "Rock Mite", has been popular in the United States, is the representative of the direct amplifier! Sales of up to 6000 sets. Introduced to China two or three years ago, after being localized by domestic enthusiasts, it was named "Super Octopus" and published twice in the "Radio" magazine, which was loved by domestic HAMs.

main indicators Power supply: 12V-13.8V (linear regulated power supply is recommended) Antenna: 50 ohm, unbalanced Transmitting power: 12V /5W (use 12V power supply, long time transmission will be slightly reduced, use D882 output) Frequency: transmitting local oscillator frequency: 7023kHz; receiving local oscillator frequency: about 7023-7026KHz Working mode: CW

Circuit principle        The core of the receiving part is an NE602, which includes a balanced mixer inside. The signal from the antenna passes through two crystal filters and then enters the mixer. The oscillator circuit composed of 9018 sends out the local oscillator signal at the same time, and the two signals pass through the mixer. Mixing, the SSB/CW signal is directly converted into audio, and the audio output from NE602 is sent to NE5532 for active low-pass filtering and audio amplification, thus completing the entire receiving process. Therefore, a receiver that directly mixes the radio frequency signal into audio is called a "DC receiver", and DC means direct frequency conversion. The mute circuit composed of 2N7000 field effect tube in the circuit is used to turn off the receiving when transmitting. At the same time, the audio oscillator composed of the internal timer of STC12C4052 generates sidetone and outputs it to the earphones, so that the earphones follow the shooting and produce "tick". Audio. The transmitting part uses 9018 as an oscillating circuit, and then 8050 as a buffer amplifying, and 8050 is also used as a transmitting key to control the switching of the receiving and sending circuit and the signal. The final stage is a class C amplifier composed of D882, which is amplified by a 1:4 output transformer The matched high frequency signal is filtered by LPF and then connected to the antenna.

Component selection

The magnification of 9018 is about 130, and the magnification of D882 is about 200. T1 is a 1:4 transmission line transformer. Use 0.51 mm enameled wire double-twisted wire on the FT37-43 ferrite ring (American) and wind 6 turns (refer to the figure below), and then connect the first and the tail of one coil connection.

T2 is a high frequency transformer, which is wound with 0.51 mm enameled wire on the FT37-43 ferrite ring (American), with 8 turns on the primary and 2 turns on the secondary (due to the poor consistency of the analog characteristics of the triode, if the output power is found in the experiment If it is weaker, you can change the number of turns to 9:3). L1 and L2 are high-frequency filter inductors. Use 0.51 mm enameled wire to wind 16 turns on the T37-2 iron powder core magnetic ring (American style), about 25cm, and the inductance is about 1uH. All capacitors less than 1000pF are high-frequency ceramics, capacitors greater than 1uF are aluminum electrolytic capacitors, and all resistors are 1/4W 5% fixed resistors.

Effect picture after installation of shell + finished board (for reference during installation)